The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs, wherein each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometric size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling-down process generally provides benefits by increasing production efficiency and lowering associated costs.
However, since feature sizes continue to decrease, fabrication processes continue to become more difficult to perform. The fabrication processes include various common processes, such as deposition processes, photolithography process, etching processes, and the like. Therefore, it is a challenge to form reliable semiconductor devices at smaller and smaller sizes.